Merge branch 'develop' into feature/epub-module-refactoring
Elimination of remaining endemic data structures.

This commit eliminates the remaining usages of JSON data structures that
were endemic to readium-js. Currently, only data structures accepted by
readium-shared-js are produced and used.
Propagate the package-global rendition_spread property
Fix a small reference error in error logging
Replace recursion with iteration in SMIL parsing.

The recursive approach has been using up call stack.

Modern browsers can suffer from call stack limits as low as 20k frames - see:

http://stackoverflow.com/a/7828803

This would cause problems for publications containing more than about
20k spine items, which isn't quite outside the domain of possibility.
Merge pull request #42 from readium/feature/epub-module-refactoring

Feature/epub module refactoring